Processors (MPUs: Micro Processing Units) for built-in use employing a multi-core system embedded with a plurality of central processing unit (CPU) cores have been developed. These processors are mounted in one chip with peripheral devices included therein.
A technique of operating a plurality of different operating systems (OSs) on a multi-core CPU is known. Further, means for notifying a single interrupt request (IRQ) to a plurality of CPU cores is known as a function of the MPU. Further, the MPU can set to which CPU core the interrupt request should be allocated based on a register setting.
Another technique shown in FIG. 9 is known, for example, for transferring audio data (e.g., pulse code modulation (PCM) sound) from a CPU inside an MPU 50 to an audio DAC (ADAC) 51 through an Inter-IC Sound (I2S) bus. The I2S is a serial communication format made by PHILIPS (registered trademark) and forming an interface device of audio data. According to the I2S specification, PCM sound or compressed sound (μ-law, ADPCM or the like) can be transmitted to the ADAC 51 through the I2S bus. Further, in FIG. 9, an Inter-Integrated Circuit (I2C) bus is a serial bus for controlling devices developed by PHILIPS (registered trademark). The ADAC 51 converts the audio data into stereo sound. The DAC is a D/A converter. The analog sound (stereo) output from the ADAC 51 is reproduced in a speaker 59.
Further, as shown in FIG. 10, for example, a sound server 56 is known that receives audio data output from a plurality of OSs through a network, mixes the plurality of pieces of audio data that are received with audio data received in the same client PC, and converts the data into a single stereo sound. In the example shown in FIG. 10, audio data output from application programs [A] and [B] (abbreviated as application [A] 53 and application [B] 54) of a UNIX (registered trademark) server 52 is transmitted to a client PC 55 using a TCP/IP. The sound server 56 of the client PC 55 mixes the audio data transmitted from a UNIX server 52 and the audio data output from an application program [C] (abbreviated as application [C] 57 in FIG. 10) to output the mixed data to a sound driver 58. In UNIX (registered trademark), for example, well-known Esound and Pulse Audio may be used as the sound server 56.
Other techniques related to the present invention include the ones disclosed in Patent literatures 1 to 3. For example, a host monitoring control system by a multi-system control processor disclosed in Patent literature 1 determines occurrence of a failure in a host according to detection of timeout of a monitoring timer installed for each host. Upon determination that the recovery is required, the host specified as a first recovery starts a recovery process. In this way, the failure in the host is promptly detected without intervention by an operator, thereby uniquely determining the recovery host that performs the rest of the processing.